Manchester United manager Louis van Gaal says he would be upset if it turns out to be true that the club has approached former Chelsea manager Jose Mourinho behind his back.

Jose Mourinho has allegedly made it clear he is ready to replace Louis van Gaal if the Dutchman is sacked or departs Old Trafford at the end of the season.(AP Photo)

Manchester United manager Louis van Gaal says he would be upset if it turns out to be true that the club has approached former Chelsea manager Jose Mourinho behind his back.

Embattled United boss van Gaal takes his team to Sunderland on Saturday with speculation mounting that Mourinho is waiting in the wings to take charge at Old Trafford.

United have refused to deny reports they have spoken to Mourinho in recent weeks following their team’s slump and the Portuguese is said to have made it clear he is ready to replace van Gaal if the Dutchman is sacked or departs at the end of the season.

Van Gaal concedes it is plausible the club have made contact with Mourinho in secret, but he is hoping that is not the case.

“Then I shall be disappointed (if contact has been made),” he said.

“Because that is the consequence of what I have said. In a football world that is possible, I know, but I do not think that.

“I have a relationship with (executive vice chairman) Ed (Woodward) and the Glazers, they (would) tell me I think.”